Repro Physiology Exam 3: Fertilization, Maternal Recognition, Controling Estrus, Pregnancy, partition, and puberty

T/F: The primary cause of ovarian cysts in cattle is considered to be reduced expression of aromatase in the granulosa cells of the periovulatory follicle

False: The primary cause of ovarian cysts in cattle is considered to be reduced expression of aromatase in the granulosa cells of the periovulatory follicle

T/F: The Y-Chromosome expresses SRY which encodes the protein TDF (testis determine factor), whereas the X-chromosome expresses SRX which encodes ODF (ovary determine factor

False: The Y-Chromosome expresses SRY which encodes the protein TDF (testis determine factor), whereas the X-chromosome expresses SRX which encodes ODF (ovary determine factor

T/F: If you ovariectomize an anestrous ewe, you would expect the release of LH from the anterior pituitary gland to increase

True: If you ovariectomize an anestrous ewe, you would expect the release of LH from the anterior pituitary gland to increase

T/F: Women with polycystic ovarian syndrome (PCOS) typically have 3-4 un-ovulated follicles (each 4 cm in diameter) present on their ovaries

False: Women with polycystic ovarian syndrome (PCOS) typically have 3-4 un-ovulated follicles (each 4 cm in diameter) present on their ovaries

T/F: Dogs have a endotheliochorial type placenta

True: Dogs have a endotheliochorial type placenta

T/F: Social factors are the most important permissive factor that regulates the onset of puberty in sheep

False: Social factors are the most important permissive factor that regulates the onset of puberty in sheep

T/F: If I ovariectomize a pregnant pig, she will maintain her pregnancy

False: If I ovariectomize a pregnent pig, she will maintain her pregnancy

T/F: During sexual differentiation in the female, the mullerian ducts develop into the ovary, oviduct, uterus, and portions of the vaginia

False: During sexual differentiation in the female, the mullerian ducts develop into the ovary, oviduct, uterus, and portions of the vaginia

• Only fallopion tubes, uterus, and proximal vaginia

T/F: daylight-induced changes in the release of serotonin from the pineal gland will affect the onset of puberty in seasonal breeders

False: Daylight-induced changes in the release of serotonin from the pineal gland will affect the onset of puberty in seasonal breeders

T/F: During sexual differentiation in the female, the secretion of estradiol from the fetal gonads feminizes the female brain

False: During sexual differentiation in the female, the secretion of estradiol from the fetal gonads feminizes the female brain

When is totipotency of a developing embryo lost at?

16-cell stage loses its totipotency

5a-dihydrotestosterone (5a-DHT) is a more potent androgen than testosterone. Both testosterone and 5a-DHT will be converted to estradiol by the action of aromatase

False: Only testosterone converted by aromatse will convert into estradiol, not 5a-DHT!!!!

T:F: a-fetoprotein is a Y chromosome-linked protein that induces masculinization of the male brain

False: a-fetoprotein is a Y chromosome-linked protein that induces masculinization of the male brain

T/F: Within the placenta of a mid-pregnant ewe you would expect to observe expression of the cytochrome P450 side chain cleavage (P450 SCC) which converts cholesterol to pregnenolone, as well as 3B-HSD, which converts pregnenolone to progesterone

True: Within the placenta of a mid-pregnant ewe you would expect to observe expression of the cytochrome P450 side chain cleavage (P450 SCC) which converts cholesterol to pregnenolone, as well as 3B-HSD, which converts pregnenolone to progesterone

The “developmental clock” in ewe lambs is considered mature by 6 months of age. If a ewe lamb is born in the Fall, when will she reach puberty?

The ewe lamb can still become mature but will NOT in puberty. Maturation of hypothalumic pituitary gonad axis will occur next fall

What is the primary permissive signal affecting puberty in cattle?

Body weight

What are the 5 steps to fertilization?

1. Sperm must penetrate through COC

2. Binding of sperm to the zona pellucida of the oocyte

3. Acrosome reaction

4. Fusion of sperm and oocyte

5. Activation of oocyte

Describe the 1st step of fertilization: Sperm penetrate the COC

• sperm enzyme hyalurondase destroys hyaluronic acid from being secretead from cummulus cells, allowing sperm to get to oocyte

Describe the 2nd step of fertilization: Binding of sperm and ZP of oocyte

• capacittation of sperm exposes egg-binding protein

• Egg-binding protein and ligand ZP3 of ooctye bind together

Describe the 3rd step of fertilization: Acrosome reaction

• Plasma membrane and outer acrosomal membrane fuse together to form channels

• Acosin is released, penetrating though ZP

• Hyperactivation occurs

• Penetration

Describe the 4th step of fertilization: Fusion of sperm and oocyte

• Sperm will be loged in perivitelline space and engolfed by vitelline membrane

• BLOCK POLYSPERMY!!!!!! zona and vitelline block: chemical alteration

Describe the final and 5th step of fertilization: Activation

• Cortical reaction: ca2+ increases, releasing cortical granules

• Completion of meiosis 2

• Formation of pronucleus and sygamy